Learning to See the Invisible Hello! If you have arrived here, it is probably for one of three reasons.Perhaps you are a student curious about how the world works.Perhaps you are a teacher looking for ways to make science come…
How Can We Determine the Exact Proportions in Which Two Chemical Substances React? 1. The challenge In many professions it is necessary to calculate quantities with precision. A tailor estimates the amount of fabric needed to make a garment, and…
Is It Possible to Calculate the Size of a Molecule Without Seeing It? 1. The challenge We cannot see a molecule with the naked eye. So how do we know how large it is? Science answers this question in a…
How Can an Ordinary Material Like Flour Cause an Explosion? 1. The challenge The key idea is surface area. When a combustible material is dispersed into very fine particles, each particle becomes surrounded by oxygen. If a source of heat…
How Can a Chemical Reaction Produce the Force Needed to Launch a Rocket? 1. The challenge When two substances react chemically, they can produce new materials and release energy. In this experiment, vinegar (acetic acid) reacts with sodium bicarbonate and…
How can we tell whether an object moves at a constant velocity? 1. The Challenge According to Newton’s First Law, an object will remain at rest or move with constant velocity unless an external force changes its state. In everyday…
How Much “Fuel” Does a Rocket Need to Reach the Highest Possible Altitude? 1. The challenge Space rockets must generate enough acceleration to overcome Earth’s gravity. However, there is an important problem: the fuel needed to produce thrust also increases…
Is It Possible to Generate Energy Using an Electric Motor? 1. The challenge At first glance, it might seem possible. If you connect an electric motor to a battery, the motor begins to spin. If that motor is used to…
Can the Heat Produced by Your Body Become Useful Energy? 1. The challenge The human body constantly releases energy in the form of heat. This happens because our cells transform the chemical energy from food into energy used to move,…
How Can Scientists Measure Something They Cannot See Directly? 1. The challenge Many of the most important objects in science—atoms, nuclei, and subatomic particles—are far too small to observe with the naked eye. Even with advanced instruments, they often cannot…
